CVE-2026-83578: Integer underflow (wrap or wraparound) in Windows PowerShell allows an unauthorized attacker to execute code o

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CRITICAL 9.8REMOTEWATCHLIST

CVE-2026-83578 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer underflow (wrap or wraparound) in Windows PowerShell allows an unauthorized attacker to execute code over a network.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 35%)
CISA exploited list	No
Weakness	CWE-122, CWE-190, CWE-191
Published	2026-10-13
Last modified	2026-10-16

Publisher (CNA): Microsoft Corporation

Last updated 2026-10-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-10-13 19:20 UTCPublished CVE record published
2026-10-16 16:21 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · gcl · FIXED · 2.7.1-12.fc46 · FEDORA-2026-ff383a759b · source

sudo dnf upgrade --advisory=FEDORA-2026-ff383a759b

Fedora ELN · mozjs140 · FIXED · 140.13.0-5.eln159 · FEDORA-2026-f7ed0026e0 · source

sudo dnf upgrade --advisory=FEDORA-2026-f7ed0026e0

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-83578?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-83578 being exploited?

CVE-2026-83578 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-83578 affect?

CVE-2026-83578 affects affected software. Severity is critical (CVSS 9.8). Integer underflow (wrap or wraparound) in Windows PowerShell allows an unauthorized attacker to execute code over a network.

How urgent is CVE-2026-83578?

Priority 64/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Windows vulnerabilities · PowerShell vulnerabilities

References

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